If A is the adjacenty matrix associated with a simple graph, then the (i,j) entry in A+ A2 + A3 + At is the number of paths of length exactly 4 from node i to node j the number of paths of lengths 1, 2, or 3 from node i to node j ( the number of routes of not more than 4 edges from node i to node j the number of routes of lengths 1, 2, or 3 from node i to node j the number of routes of length exactly 4 from node i to node j (the number of edges joining nodes i and j ()the number of paths of not more than 4 edges from node i to node j